// Copyright 2018 the V8 project authors. All rights reserved.
// Use of this source code is governed by a BSD-style license that can be
// found in the LICENSE file.

#ifndef V8_CODE_REFERENCE_H_
#define V8_CODE_REFERENCE_H_

#include "src/handles.h"
#include "src/objects/code.h"

namespace v8 {
namespace internal {

    class Code;
    class CodeDesc;

    namespace wasm {
        class WasmCode;
    }

    class CodeReference {
    public:
        CodeReference()
            : kind_(NONE)
            , null_(nullptr)
        {
        }
        explicit CodeReference(const wasm::WasmCode* wasm_code)
            : kind_(WASM)
            , wasm_code_(wasm_code)
        {
        }
        explicit CodeReference(const CodeDesc* code_desc)
            : kind_(CODE_DESC)
            , code_desc_(code_desc)
        {
        }
        explicit CodeReference(Handle<Code> js_code)
            : kind_(JS)
            , js_code_(js_code)
        {
        }

        Address constant_pool() const;
        Address instruction_start() const;
        Address instruction_end() const;
        int instruction_size() const;
        const byte* relocation_start() const;
        const byte* relocation_end() const;
        int relocation_size() const;
        Address code_comments() const;
        int code_comments_size() const;

        bool is_null() const { return kind_ == NONE; }
        bool is_js() const { return kind_ == JS; }
        bool is_wasm_code() const { return kind_ == WASM; }

        Handle<Code> as_js_code() const
        {
            DCHECK_EQ(JS, kind_);
            return js_code_;
        }

        const wasm::WasmCode* as_wasm_code() const
        {
            DCHECK_EQ(WASM, kind_);
            return wasm_code_;
        }

    private:
        enum { NONE,
            JS,
            WASM,
            CODE_DESC } kind_;
        union {
            std::nullptr_t null_;
            const wasm::WasmCode* wasm_code_;
            const CodeDesc* code_desc_;
            Handle<Code> js_code_;
        };

        DISALLOW_NEW_AND_DELETE()
    };
    ASSERT_TRIVIALLY_COPYABLE(CodeReference);

} // namespace internal
} // namespace v8

#endif // V8_CODE_REFERENCE_H_
